Injection device

ABSTRACT

Injection device in which a first chamber, located at the pointed end of the injector needle and partly defined by the seat for the end of the needle, permanently communicates with a source of fuel under pressure, such as the fuel injection pump. A second chamber into which the rear end portion of the needle extends is put in communication by a distributor valve alternately with said source of fuel and with an enclosure in which a substantially lower pressure prevails, such as a pressure in the neighborhood of atmospheric pressure.

llnited States Patent [1 1 Regneault et al.

[ Dec. 11, 1973 INJECTION DEVICE Inventors: Marcel Regneault, Colombes; Jean Perez, Levallois-Perret, both of France [73] Assignee: Automobiles Peugeot, Paris, France Filed: June 26, 1972 21 App]. No.: 266,252

[30] Foreign Application Priority Data v July 8, 1971 France 7125045 US. Cl 239/96, 239/533, 239/585 Int. Cl F02m 41/16 Field of Search 239/533, 584, 585,

References Cited UNITED STATES PATENTS 8/1972 Monpetit et al. 239/585 X 9/1969 l-Iuber 239/585 X 3,610,529 10/1971 Huber 239/585 X 2,788,246 4/1957 Nichols 239/96 3,409,226 11/1968 Steiger 239/96 X Primary Examiner-M. Henson Wood, .lr. Assistant Examiner-Michael Y. Mar Attorney-Robert S. Swecker [57] ABSTRACT 5 Claims, 1 Drawing Figure INJECTION DEVICE The present invention relates to internal combustion engines of the fuel injection type and more particularly concerns electrically or electronically controlled injection devices in which the injector needle is shifted from its seat by the action of the pressure of the fuel.

Two main categories of devices for actuating electromagnetically or electronically controlled injectors are known. In the first category, the needle of the injector is raised directly by the action of magnetic means, the needles constituting the moving part of the magnetic means. This device has the drawback of requiring a large magnetic force to overcome the force of the needle-returning spring and possibly the hydraulic pressure which is exerted on the rear end face of the needle and acts in the same direction as the return spring.

In the second category, the needle of the injector is raised off its seat by the action of the pressure of the fuel in an annular chamber located in the vicinity of the front end of the needle and partly defined by the seat with which the needle co-operates. This chamber is put under pressure or cut off from pressure under the control of a closing member which is actuated by an electromagnetic device and the needle is caused to move back against its seat by a spring as soon as the annular chamber is cut off from the pressure. The essential drawback of this arrangement is that it encourages the rebound of the needle which results in leakage or seeping of fuel the poor combustion of which results in the formation of smoke, polluting gases and carbon deposit. Further, the evolution in the rating of the needlereturn spring over a period of time owing to fatigue gradually modifies the initial setting of the injection and this also results in a drop in the efficiency of the engine. An object of the invention is to avoid these various drawbacks and in particular the risk of rebound of the needle of the injector, to improve the sealing of this needle on its seat and to render the rising of the needle off its seat unaffected by a variation in the rating of its return spring.

The invention provides an injection device comprising an injector carrier and an injector, a needle slidably mounted in the injector, a first chamber in the vicinity of the point of the needle and partly defined by the seat with which the needle cooperates, and a second chamber provided in the injector or the injector carrier and located at the end of the needle opposed to the point, wherein the first chamber is permanently connected to a source of fuel under pressure, such as the injection pump, whereas the second chamber is connected to a distributor valve adapted to put it alternately in communication with said source of fuel under pressure or with an enclosure in which prevails a substantially lower pressure, for example a pressure in the neighbourhood of atmospheric pressure.

In such an arrangement, there is employed a variation in the force exerted by the pressure on the rear end of the needle of the injector for applying the needle against its seat when the pressure is high. and allowing the needle to move away from its seat under the action of the relatively high pressure constantly prevailing in the first chamber when the pressure in the second chamber resumes a low value.

According to another feature of the invention, a jet is provided in each of the conduits respectively connected to the first and second chambers whereby it is possible to control the rapidity of the movements of the needle away from and toward the seat and consequently the fuel flow during injection.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the single FIGURE which is a sectional view of an injector and injector carrier according to the invention.

The FIGURE shows an injector carrier 1 in which are mounted the injector proper and its actuating device. The injector comprises an injector head 2 which is fixed to the injector carrier by a screwthreaded flange 3 and in which a needle 4 is slidably mounted. The injector carrier has a bore or aperture 5 into which the rear end portion of the needle extends, a return spring 6 bearing against the end of the needle. At the head end of the injector, an aperture 7 and a seat 8 are provided, the nose or point of the needle cooperating with this seat. An annular chamber 9 is provided and is connected by a conduit 10a, 10b to the delivery side of the injection pump (not shown). A first jet [1 is interposed between the conduits 10a, 10b.

The injector carrier 1 has a hollow lateral extension portion 1a in which are disposed a distributing valve 12 and an electromagnet 13. A connector lb is adapted to be connected to the delivery side of the injection pump. The distributing valvemay be, for example, of the general type disclosed in US. Patent application Ser. No. 266,235 filed by the applicants. This type of distributing valve is preferably employed for the reasons indicated in the aforementioned patent application, but it must be understood that other types of distributing valve may be employed in the injection device according to the invention. It will merely be briefly mentioned that this distributing valve 12 comprises a composite body consisting ofa plurality of members 14, 15, 16, 17 and a double closing member 18 having two guide stems 19, 20, one of which is solid and the other grooved. These stems are slidably mounted in bores 21, 22 formed in the body of the distributing valve. The two end faces of the closing member are subjected to equal pressure forces: in the chosen embodiment, these two faces have equal sections and are subjected to the pressure of the fuel supplied by the injection pump, whereas the two chambers 23, 24 defined by the double closing member 18 and the body are connected as follows: the chamber 23 is connected to the chamber 5 formed in the injector carrier by way of a conduit 25 in which is inserted a second jet 26 and the chamber 24 is connected by way of conduits 27, 28 and a coupling 29 to an enclosure (not shown) in which prevails a pressure in the neighborhood of atmospheric pressure.

The injection device operates in the following manner.

When the electromagnet 13 is non-energized, the chamber 5 is in communication with the delivery side of the injection pump by way of the conduit 25, the jet 26 and the chambers 23, 22 and this has for effect strongly to apply the needle 4 against its seat, since the opposing pressure exerted in the chamber 9 is only applied against a reduced area of the needle, this area being reduced by the area of the seat 8. The small spring 6 also tends to apply the needle against its seat.

When the electromagnet 13 is energized, the slide valve member 18 is shifted to the right as viewed in the FIGURE, so that chamber 5 is connected to the atmosphere through the path 25, 26, 23, 24, 27, 28, 29.

Under the effect of the pressure which is permanently maintained in the chamber 9, the needle is moved away from its seat and the injection can occur until the supply of current to the electromagnet is cut off. At this moment, the double closing or valve member 18 resumes the illustrated position and the pressure is reestablished in the chamber 5 so that the needle is urged back onto its seat with no possibility of rebound of the needle owing to the incompressibility of the liquid contained in the chamber 5 and its rapid pressurization. Thus the serious drawbacks of known devices are overcome and the risk of rebound of the needle is avoided. The moving of the needle away from its seat is practically unaffected by a variation in the rating or force of its return spring since the function of the spring is quite secondary.

It will also be observed that the jets 11 and 26 still further improve the conditions of operation of this device. The jet 26 inserted in the conduit 24 controls the rapidity with which the needle rises and falls relative to its seat and consequently the form of the start and end of the injection law. The jet 11 inserted in the conduit a, 10b controls the rate of flow of the fuel during the injection and eliminates, as explained in the aforementioned patent application, the harmful effects produced by the deposit of carbon, among which may be mentioned a modification in the rate of flow of the injected fuel.

Having now described our invention what We claim as new and desire to secure by Letters Patent is:

1. An injection device comprising an injector carrier, means defining an injector carried by the carrier, an injector needle having a pointed end portion and slidably mounted in the injector, means defining a seat in the injector for the pointed end portion of the needle, a first chamber in the injector in the vicinity of the pointed end portion of the needle and partly defined by the seat, means defining a second chamber, the needle having a rear end portion opposed to the pointed end portion and extending into the second chamber and having a surface partly defining the second chamber, passage means for permanently connecting the first chamber to a source of fuel under pressure, means defining an enclosure in which prevails a pressure which is substantially lower than the pressure of said source of fuel, a distributor valve comprising means defining a body, means defining a bore in the body, a closing member slidable in the bore, means for subjecting opposite ends of the closing member to the same pressure force, two opposite sealing faces on the closing memher, two opposed seats on the body for co-operation with the sealing faces, electromagnetic means combined with the closing member for shifting the closing member in the body between a position in which a first of said faces sealingly engages a first of said seats and a position in which a second of said faces sealingly engages a second of said seats, the closing member defining with the body a third chamber when said first face and first seat are in engagement, the closing member defining with the body a fourth chamber when said second face and second seat are in engagement, a fifth chamber in the body capable of communicating with the third chamber and fourth chamber when the first face and first seat and the second face and second seat are respectively separated from each other, passage means putting the third chamber in communication with said enclosure, passage means putting the fourth chamber in communication with said source of fuel under pressure and passage means putting the fifth chamber in communication with said second chamber.

2. A device as claimed in claim 1, wherein the closing member has two guiding portions at opposite ends of the closing member and slidable in said bore, said sealing faces and seats being annular.

3. A device as claimed in claim 1, wherein said sealing faces and seats are frustoconical.

4. An injection device comprising an injector carrier, means defining an injector carried by the carrier, an injector needle having a pointed end portion and slidably mounted in the injector, means defining a seat in the injector for the pointed end portion of the needle, a first chamber in the injector in the vicinity of the pointed end portion of the needle and partly defined by the seat, means defining a second chamber, the needle having a rear end portion opposed to the pointed end portion and extending into the second chamber and having a surfacepartly defining the second chamber, passage means for permanently connecting the first chamber to a source of fuel under pressure, means defining an enclosure in which prevails a pressure which is substantially lower than the pressure of said source of fuel, a distributing valve, passage means connecting the second chamber to the distributing valve which is capable of putting the second chamber in communication alternately with said source of fuel under pressure and with the enclosure, the distributing valve comprising a balanced double closing member and electromagnet means for shifting the double closing member.

5. An injection device as claimed in claim 4, wherein said pressure in the enclosure is in the neighborhood of atmospheric pressure. 

1. An injection device comprising an injector carrier, means defining an injector carried by the carrier, an injector needle having a pointed end portion and slidably mounted in the injector, means defining a seat in the injector for the pointed end portion of the needle, a first chamber in the injector in the vicinity of the pointed end portion of the needle and partly defined by the seat, means defining a second chamber, the needle having a rear end portion opposed to the pointed end portion and extending into the second chamber and having a surface partly defining the second chamber, passage means for permanently connecting the first chamber to a source of fuel under pressure, means defining an enclosure in which prevails a pressure which is substantially lower than the pressure of said source of fuel, a distributor valve comprising means defining a body, means defining a bore in the body, a closing member slidable in the bore, means for subjecting opposite ends of the closing member to the same pressure force, two opposite sealing faces on the closing member, two opposed seats on the body for co-operation with the sealing faces, electromagnetic means combined with the closing member for shifting the closing member in the body between a position in which a first of said faces sealingly engages a first of said seats and a position in which a second of said faces sealingly engages a second of said seats, the closing member defining with the body a third chamber when said first face and first seat are in engagement, the closing member defining with the body a fourth chamber when said second face and second seat are in engagement, a fifth chamber in the body capable of communicating with the third chamber and fourth chamber when the first face and first seat and the second face and second seat are respectively separated from each other, passage means putting the third chamber in communication with said enclosure, passage means putting the fourth chamber in communication with said source of fuel under pressure and passage means putting the fifth chamber in communication with said second chamber.
 2. A device as claimed in claim 1, wherein the closing member has two guiding portions at opposite ends of the closing member and slidable in said bore, said sealing faces and seats being annular.
 3. A device as claimed in claim 1, wherein said sealing faces and seats are frustoconical.
 4. An injection device comprising an injector carrier, means defining an injector carried by the carrier, an injector needle having a pointed end portion and slidably mounted in the injector, means defining a seat in the injector for the pointed end portion of the needle, a first chamber in the injector in the vicinity of the pointed end portion of the needle and partly defined by the seat, means defining a second chamber, the needle having a rear end portion opposed to the pointed end portion and extending into the second chamber and having a surface partly defining the second chamber, passage means for permanently connecting the first chamber to a source of fuel under pressure, means defining an enclosure in which prevails a pressure which is substantially lower than the pressure of said source of fuel, a distributing valve, passage means connecting the second chamber to the distributing valve which is capable of putting the second chamber in communication alternately with said source of fuel under pressure and with the enclosure, the distributing valve comprising a balanced double closing member and electromagnet means for shifting the double closing member.
 5. An injection device as claimed in claim 4, wherein said pressure in the enclosure is in the neighborhood of atmospheric pressure. 